// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef UI_BASE_MODELS_MENU_MODEL_H_
#define UI_BASE_MODELS_MENU_MODEL_H_

#include "base/strings/string16.h"
#include "ui/base/models/menu_model_delegate.h"
#include "ui/base/models/menu_separator_types.h"
#include "ui/base/ui_base_export.h"
#include "ui/gfx/image/image_skia.h"
#include "ui/gfx/native_widget_types.h"

namespace gfx {
class FontList;
class Image;
}

namespace ui {

class Accelerator;
class ButtonMenuItemModel;

// An interface implemented by an object that provides the content of a menu.
class UI_BASE_EXPORT MenuModel {
public:
    // The type of item.
    enum ItemType {
        TYPE_COMMAND,
        TYPE_CHECK,
        TYPE_RADIO,
        TYPE_SEPARATOR,
        TYPE_BUTTON_ITEM,
        TYPE_SUBMENU
    };

    virtual ~MenuModel() { }

    // Returns true if any of the items within the model have icons. Not all
    // platforms support icons in menus natively and so this is a hint for
    // triggering a custom rendering mode.
    virtual bool HasIcons() const = 0;

    // Returns the number of items in the menu.
    virtual int GetItemCount() const = 0;

    // Returns the type of item at the specified index.
    virtual ItemType GetTypeAt(int index) const = 0;

    // Returns the separator type at the specified index.
    virtual ui::MenuSeparatorType GetSeparatorTypeAt(int index) const = 0;

    // Returns the command id of the item at the specified index.
    virtual int GetCommandIdAt(int index) const = 0;

    // Returns the label of the item at the specified index.
    virtual base::string16 GetLabelAt(int index) const = 0;

    // Returns the sublabel of the item at the specified index. The sublabel
    // is rendered beneath the label and using the font GetLabelFontAt().
    virtual base::string16 GetSublabelAt(int index) const;

    // Returns the minor text of the item at the specified index. The minor text
    // is rendered to the right of the label and using the font GetLabelFontAt().
    virtual base::string16 GetMinorTextAt(int index) const;

    // Returns true if the menu item (label/sublabel/icon) at the specified
    // index can change over the course of the menu's lifetime. If this function
    // returns true, the label, sublabel and icon of the menu item will be
    // updated each time the menu is shown.
    virtual bool IsItemDynamicAt(int index) const = 0;

    // Returns the font list used for the label at the specified index.
    // If NULL, then the default font list should be used.
    virtual const gfx::FontList* GetLabelFontListAt(int index) const;

    // Gets the accelerator information for the specified index, returning true if
    // there is a shortcut accelerator for the item, false otherwise.
    virtual bool GetAcceleratorAt(int index,
        ui::Accelerator* accelerator) const = 0;

    // Returns the checked state of the item at the specified index.
    virtual bool IsItemCheckedAt(int index) const = 0;

    // Returns the id of the group of radio items that the item at the specified
    // index belongs to.
    virtual int GetGroupIdAt(int index) const = 0;

    // Gets the icon for the item at the specified index, returning true if there
    // is an icon, false otherwise.
    virtual bool GetIconAt(int index, gfx::Image* icon) = 0;

    // Returns the model for a menu item with a line of buttons at |index|.
    virtual ButtonMenuItemModel* GetButtonMenuItemAt(int index) const = 0;

    // Returns the enabled state of the item at the specified index.
    virtual bool IsEnabledAt(int index) const = 0;

    // Returns true if the menu item is visible.
    virtual bool IsVisibleAt(int index) const;

    // Returns the model for the submenu at the specified index.
    virtual MenuModel* GetSubmenuModelAt(int index) const = 0;

    // Called when the highlighted menu item changes to the item at the specified
    // index.
    virtual void HighlightChangedTo(int index) = 0;

    // Called when the item at the specified index has been activated.
    virtual void ActivatedAt(int index) = 0;

    // Called when the item has been activated with given event flags.
    // (for the case where the activation involves a navigation).
    // |event_flags| is a bit mask of ui::EventFlags.
    virtual void ActivatedAt(int index, int event_flags);

    // Called when the menu is about to be shown.
    virtual void MenuWillShow() { }

    // Called when the menu has been closed.
    virtual void MenuClosed() { }

    // Set the MenuModelDelegate. Owned by the caller of this function.
    virtual void SetMenuModelDelegate(MenuModelDelegate* delegate) = 0;

    // Gets the MenuModelDelegate.
    virtual MenuModelDelegate* GetMenuModelDelegate() const = 0;

    // Retrieves the model and index that contains a specific command id. Returns
    // true if an item with the specified command id is found. |model| is inout,
    // and specifies the model to start searching from.
    static bool GetModelAndIndexForCommandId(int command_id,
        MenuModel** model,
        int* index);
};

} // namespace ui

#endif // UI_BASE_MODELS_MENU_MODEL_H_
